Controllable Carrier Type in Boron Phosphide Nanowires Toward Homostructural Optoelectronic Devices.

The p-n junction is one important and fundamental building block of the optoelectronic age. However, electrons and holes will be severely scattered in heterostructures led by the grain boundary at the alloy interface between two dissimilar semiconductors. In this work, we present boron phosphide (BP) nanowires with artificially controllable carrier type for the fabrication of homojunctions via adjusting borane/phosphine ratio during the deposition process, both prove high crystallization with fewer impurities. The homojunctions that consist of  n-type and p-type BP nanowires show apparent photovoltaic effect [external quantum efficiency ≈ 10% under a ∼0.4 pW light @ 600 nm] and the quenched photoluminescence within the junction area, which indicates the effective separation and transfer of photogenerated charge carriers at the interface. The achievement of controllable carrier type implemented in the same material ushers in a frontier for the design of nanoscale homojunctions toward advanced optoelectronic devices.